1. Field of the Invention
The present invention relates generally to dry type cleaning apparatuses and dry type cleaning methods for removing, by using solid cleaning media and without using water or solvents, dust and granular material, e.g., toner having average granular diameters of 5 μm through 10 μm. The toner is used in electrophotographic image forming apparatuses such as copiers and laser printers, where it adheres to various cleaning objects such as components having relatively complex shapes. More particularly, the present invention relates to a dry type cleaning apparatus and a dry type cleaning method with which cleaning objects can be continuously loaded and cleaned, thereby enhancing operability.
2. Description of the Related Art
Manufacturers of office equipment such as copiers, facsimile machines, and printers are actively involved in recycling activities for the purpose of realizing a resource-recycling society. Specifically, the manufactures recover used products and units from users, and disassemble, clean, and reassemble the used products to be reused as components or resin material. In order to reuse components of these products and units, toner particles adhering to disassembled components and units need to be removed and cleaned off. Thus, reduction of cleaning costs and environmental impact is a major issue.
Patent Documents 1, 2 disclose wet type cleaning apparatuses that use water and solvents for removing dirt such as toner adhering to the components and units. The cleaning apparatus disclosed in Patent Document 1 includes a mesh cleaning basket with a large aperture. A cleaning object is fixed inside the cleaning basket, and the cleaning basket is conveyed by a conveying unit such as a belt conveyer along a path on which a cleaning solvent such as cleaning jet water is sprayed. The cleaning solvent is sprayed from above and from the sides of the cleaning basket being conveyed on the path. The cleaning solvent passes through the aperture and meshes of the cleaning basket, and collides with the cleaning object to clean the cleaning object. Cleaning baskets containing cleaning objects fixed inside are continuously loaded into the conveying unit, so that plural cleaning objects are continuously cleaned.
In the cleaning apparatus disclosed in Patent Document 2, multiple granular materials such as gel, gel foam, glass, ceramics, and synthetic resin are fluidized in a cleaning tank by gas flows. Liquid such as water and silicon liquid, which have the same relative density as the granular materials, is supplied in the cleaning tank. The supplied liquid is dispersed within granular fluid layers, thereby forming solid-liquid aggregates of appropriate sizes. Accordingly, the effective gas passage area is decreased so as to increase the gas flow velocity passing through the granular layers. This generates a peculiar three-phase stream in which fluidization of granular layers is activated, and the peculiar three-phase stream is caused to collide with the cleaning object so as to enhance cleaning efficiency.
When this wet type cleaning apparatus is used for cleaning off dirt such as toner adhering to components and units, it is necessary to perform processes such as disposing of waste water including toner and drying the components after being cleaned. These processes consume large amounts of energy and have high environmental impact.
A dry type cleaning method employing air-blowing is insufficient for cleaning off toner having a high level of adhesion strength. Thus, an after-treatment is required to manually wipe off the remaining toner. Accordingly, cleaning is a bottleneck process in reusing/recycling products.
Patent Document 3 discloses a dry type cleaning apparatus that removes dust adhering to a cleaning object as follows. A rotatable container is rotated, which container contains plural cleaning objects to which dust is adhering in an electrostatic manner, and spherical or cubic contact members made of an elastic material such as flexible urethane foam. While the container is being rotated, positive/negative aero-ions necessary for neutralizing electrical charges of the cleaning objects inside the container are emitted by ignition electrodes, and the aero-ions are sprayed onto the cleaning objects. The rotatable container is a cylinder, and the cleaning objects and the contact members are inserted into the rotating cylinder from an inlet part provided on one end of the cylinder. After the cleaning objects and the contact members are moved from an upstream side to a downstream side, the cleaning objects and the contact members are retrieved separately. Cleaning objects are continuously cleaned in the above manner.
Patent Document 4 discloses a dry type cleaning apparatus including a cleaning tank with a wire-mesh inner board for mounting a cleaning object. In between the inner board and the bottom of the cleaning tank there is provided a gas blowout section. Spherical granules having diameters of 5 mm to 10 mm made of steel, alumina, ceramics, plastic, etc., are placed in the gas blowout section. The gas blowout section has an aperture through which gas can pass but the granules cannot pass. Air from the cleaning tank is introduced through an inlet provided on a top lid, and external air is taken in from an inlet provided on the bottom of the cleaning tank, thereby forming a gas flow in the cleaning tank. The gas flow incorporates the granules into jet flows, and the jet flows are made to collide with the cleaning object, so as to clean the cleaning object.
Patent Document 1: Japanese Patent No. 2791862
Patent Document 2: Japanese Laid-Open Patent Application No. 2002-28581
Patent Document 3: Japanese Patent No. 3288462
Patent Document 4: Japanese Laid-Open Patent Application No. 2003-190247
In the dry type cleaning apparatus disclosed in Patent Document 3, cleaning objects are continuously cleaned by continuously moving the cleaning objects and the contact members from an upstream side to a downstream side in the rotating cylinder. Accordingly, the cleaning objects may contact and damage each other. Therefore, it is difficult to apply this technology to fragile resin products.
With the dry type cleaning apparatus disclosed in Patent Document 4, at least one cleaning object is loaded into the cleaning tank and removed after a certain amount of time. Therefore, cleaning objects cannot be continuously cleaned by this method.